Few scientists would look for quantum mechanics at work in machinery as complex as that of photosynthesis, with multitudes of jiggling, membrane-bound proteins anchoring even more light-absorbing chromophores. But evidence is mounting that photosynthetic organisms may, in fact, capitalize on quantum effects to harness the sun’s rays.

Quantum effects may help explain the high efficiency of photosynthesis, in which more than 95% of photons absorbed by a cell serve to reduce carbon dioxide. They may . . .